Pneumatic vane motor

ABSTRACT

A pneumatic vane motor comprising a housing ( 10 ) with a cylinder ( 11 ), two end walls ( 13,14 ), and a rotor ( 18 ) journalled in the housing ( 10 ) and carrying one or more pairs of sliding vanes ( 31 ), and vane supporting pins ( 32 ) longitudinally movable in transverse bores ( 33 ) in the rotor ( 18 ) and forming spacers between two diametrically opposite vanes ( 31 ), and the rotor ( 18 ) having a coaxial bore ( 48 ) with a closed end ( 49 ) and an open end ( 50 ) closed by a removable plug ( 51 ), wherein the coaxial bore ( 48 ) intersects the transverse bores ( 33 ) and being filled with a lubricant for providing lubrication of the vane supporting pins ( 32 ).

The invention relates to a pneumatic vane motor including a housing witha cylinder, a rotor rotatively journalled in the housing and carryingone or more pairs of diametrically opposite sliding vanes for sealingcontact with the cylinder, and one or more vane supporting pins movablysupported in a transverse bores in the rotor and forming spacer meansbetween the vanes in each pair.

Pneumatic vane motors of the above type are typically used inapplications where an output torque is guaranteed even at very low speedlevels and even right from start of the motor. One example on suchapplications is air hoists where full torque output is required rightfrom the start of the motor. Another example is paint stirring wherethere is a demand for a very low speed operation, for instance 50 rpm.At such low speed levels there are no centrifugal forces strong enoughto urge the vanes into sealing contact with the cylinder. By thearrangement of vane supporting pins or spacers the vanes indiametrically opposed pairs will move each other into a continuoussealing contact with the cylinder and thereby ensure a full torqueoutput even at very low speed levels or as soon as pressure air issupplied to the cylinder. The vane supporting pins may be combined withsprings for compensating for specific geometrical shapes of the cylinderand to ensure that no play is left between the vanes and the cylinderwall in any angular position of the rotor.

A problem concerned with air motors of this type is that the vanesupporting pins tend to be exposed to friction forces and mechanicalwear and eventually get seized, which means that the vanes would behindered from performing their sliding movements which is crucial forthe motor operation. This problem is particularly accentuated at motorspowered by oil free air where no lubrication at all is supplied to themotor.

A main object of the invention is to provide a pneumatic vane motorwherein the vane supporting pins are prevented from being exposed toundesired friction forces and mechanical wear and ensuring an extendedservice life of the motor.

Further objects and advantages of the invention will appear from thefollowing specification and claims.

A preferred embodiment of the invention is described below in detailwith reference to the accompanying drawing.

In the drawing

FIG. 1 shows a longitudinal section through a pneumatic vane motoraccording to the invention.

FIG. 2 shows a cross section along line II-II of the motor in FIG. 1.

FIG. 3 shows on a larger scale a fragmentary view of the motor in FIG.1.

The motor illustrated in the drawing comprises a housing 10, a cylinder11 with an inner cylindrical wall 12, a rear end wall 13, and a forwardend wall 14. The end walls 13,14 are secured to the cylinder 11 byscrews 15,16. A rotor 18 is rotatively journalled in the housing 10 viatwo bearings 19,20 supported in the end walls 13,14. The rotor 18 has aforward end 23 extending out of the housing 10 and adapted to beconnected to equipments to be driven by the motor, and a rear end 24covered by an end cover 25. The cylinder 11 comprises alternative airinlet and outlet openings 26,27 connected to non-illustrated controlvalves for powering the rotor in alternative directions of rotation.

The rotor 18 has six radially extending identical slots 30 each carryinga sliding vane 31. The slots 30 and vanes 31 are arranged in three pairsequally distributed along the circumference of the rotor 18, and eachpair comprising two diametrically opposite vanes. Moreover, the rotor 18is provided with three identical transverse bores 33 each connecting twoopposite slots 30 and comprising a vane supporting pin 32. As beingclearly illustrated in FIG. 3 each vane supporting pin 32 comprises asleeve shaped element 34 with a closed bottom end 36 and an open end 35,a spindle shaped stud member 38 extending into the sleeve shaped element33 via the open end 35, and a compression spring 40 located at thebottom end 34 of the sleeve shaped element 33 and arranged to exert abias force on the stud member 38. The stud member 38 and the sleeveshaped element 34 have interacting shoulders 43,44 for limiting theinward movement of the stud member 38 relative to the sleeve shapedelement 34.

In order not to overload FIG. 2 with reference numbers just one vane 31,one slot 30 and one vane supporting pin 32 are provided with referencenumbers. The vanes 31, slots 30, and pins 32 are identical to each otherin all three pairs.

The rotor 18 is provided with a co-axially extending bore 48. This bore48 has a closed end 49 and an open end 50, and the open end 50 is closedby removable plug 51. The bore 48 intersects all of the transverse bores33 and is filled with a lubricant, preferably grease, for lubricatingthe vane supporting pins 32. Accordingly, the bore 48 forms a reservoirfor lubricant which is in constant contact with the vane supporting pins32 to accomplish a more or less permanent lubrication of the vanesupporting pins 32 in their reciprocating movements relative to therotor bores 33. Although not illustrated in the drawing the sleeveelements 34 may be provided with lateral openings to let in somelubricant into the sleeve elements 34 to lubricate the contact surfacesbetween the sleeve elements 34 and the studs 38. However, the relativemovements between the studs 38 and the sleeve elements 34 are very shortand an initial lubrication of these parts at assembly may very well beenough. The lubricant reservoir formed by the axial bore 48 may befilled and refilled via the open end 50 of the bore 48 as the plug 51 isremoved.

A small amount of grease may leak past the vane supporting pins 32 intothe vane slots 30, but there would be no harm to the motor. On thecontrary, the sliding movements of the vanes 31 would be facilitated andthe mechanical wear of the vanes 31 would be reduced.

The new lubrication arrangement for the vane supporting pins 32 resultsin a substantially reduced mechanical wear and a considerably extendedservice life and/or service intervals of the motor.

The embodiments of the invention are not limited to the describedexample but may be freely varied within the scope of the claims. Forinstance, the number of vanes is not limited to six. Other practicalnumbers of vanes are two or four. It is important though that they arearranged in pairs for enabling vane supporting pins to be provided.

1-6. (canceled)
 7. A pneumatic vane motor comprising: a housing with acylinder; a rotor rotatably journalled in the housing and carrying atleast one pair of sliding vanes for sealing contact with the cylinder,wherein the vanes in each pair are disposed diametrically opposite eachother; and at least one vane supporting pin longitudinally movable inone or more transverse bores in the rotor and forming a spacer betweenthe two diametrically opposite vanes of each pair, and wherein the rotorhas a coaxially extending bore intersecting said one or more transversebores and forming a lubricant reservoir for continued supply oflubricant to the at least one vane supporting pin.
 8. The vane motoraccording to claim 7, wherein: said bore has a closed end and an openend, and said open end is closed by a removable plug.
 9. The vane motoraccording to claim 7, wherein each vane supporting pin comprises aspring for compensating for plays between the vane supporting pin andthe vanes.
 10. The vane motor according to claim 8, wherein each vanesupporting pin comprises a spring for compensating for plays between thevane supporting pin and the vanes.
 11. The vane motor according to claim9, wherein each vane supporting pin further comprises: a sleeve shapedelement with a closed bottom end and an open end; and a spindle shapedstud member movably received in said sleeve shaped element through saidopen end, and wherein said spring comprises a compression spring locatedbetween the bottom end of said sleeve shaped element and the studmember.
 12. The vane motor according to claim 10, wherein each vanesupporting pin further comprises: a sleeve shaped element with a closedbottom end and an open end; and a spindle shaped stud member movablyreceived in said sleeve shaped element through said open end, whereinsaid spring comprises a compression spring located between the bottomend of said sleeve shaped element and the stud member.
 13. The vanemotor according to claim 11, wherein said sleeve shaped element and saidstud member comprise interacting shoulders for limiting an inwardmovement of said stud member relative to said sleeve shaped element. 14.The vane motor according to claim 12, wherein said sleeve shaped elementand said stud member comprise interacting shoulders for limiting aninward movement of said stud member relative to said sleeve shapedelement.
 15. The vane motor according to claim 7, wherein the number oftransverse bores and the number of vane supporting pins are just one foreach pair of vanes.
 16. The vane motor according to claim 8, wherein thenumber of transverse bores and the number of vane supporting pins arejust one for each pair of vanes.
 17. The vane motor according to claim9, wherein the number of transverse bores and the number of vanesupporting pins are just one for each pair of vanes.
 18. The vane motoraccording to claim 10, wherein the number of transverse bores and thenumber of vane supporting pins are just one for each pair of vanes. 19.The vane motor according to claim 11, wherein the number of transversebores and the number of vane supporting pins are just one for each pairof vanes.
 20. The vane motor according to claim 12, wherein the numberof transverse bores and the number of vane supporting pins are just onefor each pair of vanes.
 21. The vane motor according to claim 13,wherein the number of transverse bores and the number of vane supportingpins are just one for each pair of vanes.
 22. The vane motor accordingto claim 14, wherein the number of transverse bores and the number ofvane supporting pins are just one for each pair of vanes.